Subject: Re: bug#11513: 24.1.50; raise-frame never raise the foreground window on Windows

From: Eli Zaretskii <[email-masked]>
Date: Mon, 28 May 2012 20:28:13 +0300

> Date: Thu, 24 May 2012 15:04:59 +0900
> From: Kazuhiro Ito <[email-masked]>
> Cc: [email-masked], [email-masked], [email-masked]
> 
> > > raise-frame always make the unexpected result when Emacs frame is
> > > the foreground window (I mean Emacs frame is colored as active window)
> > > and behind of other application window(s).  And, as I described
> > > previously, If Emacs frame is not the foreground window raise-frame
> > > correctly works.
> > 
> > But the default behavior on Windows is that a window that is lowered
> > loses its focus.  You need to click into it to get focus there.  So
> > how come a lowered window still has focus for you?
> 
> When I run lower-frame function in Emacs frame interactively, Emacs
> frame is brought behind of other application window(s) but has focus.
> Key inputs are passed to lowered frame.  I tested 4 Windows PC, and
> all PCs show the same behavior.

Sorry, I was confused.  You are right, the focus isn't lost.

Anyway, I don't think it is a good idea to modify the reaction to the
WM_EMACS_SETFOREGROUND message, because it is also used by
x-focus-frame, which is not supposed to raise the frame to the top of
the Z-order, unless it is strictly necessary.  And if the frame is
already a foreground frame, raising it isn't necessary.

So instead I introduced a new message, WM_EMACS_BRINGTOTOP, and used
that in raise-frame.  The diffs are below (installed as revision
108409 on the trunk).

Thanks.  I'm closing this bug report.

=== modified file 'src/ChangeLog'
--- src/ChangeLog	2012-05-28 07:13:45 +0000
+++ src/ChangeLog	2012-05-28 17:22:40 +0000
@@ -1,3 +1,17 @@
+2012-05-28  Eli Zaretskii  <[email-masked]>
+
+	* w32term.c (my_bring_window_to_top): New function.
+	(x_raise_frame): Use handle returned by DeferWindowPos, which
+	could be different from the original one.  Call
+	my_bring_window_to_top instead of my_set_foreground_window.
+	(Bug#11513)
+
+	* w32fns.c (w32_wnd_proc): Accept and process WM_EMACS_BRINGTOTOP
+	by calling BringWindowToTop.
+
+	* w32term.h (WM_EMACS_BRINGTOTOP): New message.
+	(WM_EMACS_END): Increase by one.
+
 2012-05-28  Paul Eggert  <[email-masked]>
 
 	* bidi.c (bidi_mirror_char): Put eassert before conversion to int.

=== modified file 'src/w32fns.c'
--- src/w32fns.c	2012-05-25 18:19:24 +0000
+++ src/w32fns.c	2012-05-28 17:22:40 +0000
@@ -3663,6 +3663,7 @@ w32_wnd_proc (HWND hwnd, UINT msg, WPARA
     case WM_EMACS_SHOWWINDOW:
       return ShowWindow ((HWND) wParam, (WPARAM) lParam);
 
+    case WM_EMACS_BRINGTOTOP:
     case WM_EMACS_SETFOREGROUND:
       {
         HWND foreground_window;
@@ -3680,6 +3681,8 @@ w32_wnd_proc (HWND hwnd, UINT msg, WPARA
           foreground_thread = 0;
 
         retval = SetForegroundWindow ((HWND) wParam);
+        if (msg == WM_EMACS_BRINGTOTOP)
+          retval = BringWindowToTop ((HWND) wParam);
 
         /* Detach from the previous foreground thread.  */
         if (foreground_thread)

=== modified file 'src/w32term.c'
--- src/w32term.c	2012-05-18 08:36:50 +0000
+++ src/w32term.c	2012-05-28 17:22:40 +0000
@@ -3492,6 +3492,12 @@ my_destroy_window (struct frame * f, HWN
 	       (WPARAM) hwnd, 0);
 }
 
+static void
+my_bring_window_to_top (HWND hwnd)
+{
+  SendMessage (hwnd, WM_EMACS_BRINGTOTOP, (WPARAM) hwnd, 0);
+}
+
 /* Create a scroll bar and return the scroll bar vector for it.  W is
    the Emacs window on which to create the scroll bar. TOP, LEFT,
    WIDTH and HEIGHT are the pixel coordinates and dimensions of the
@@ -5600,24 +5606,27 @@ x_raise_frame (struct frame *f)
       HDWP handle = BeginDeferWindowPos (2);
       if (handle)
 	{
-	  DeferWindowPos (handle,
-			  FRAME_W32_WINDOW (f),
-  			  HWND_TOP,
-  			  0, 0, 0, 0,
-  			  SWP_NOSIZE | SWP_NOMOVE | SWP_NOACTIVATE);
-
-	  DeferWindowPos (handle,
-			  GetForegroundWindow (),
-			  FRAME_W32_WINDOW (f),
-			  0, 0, 0, 0,
-			  SWP_NOSIZE | SWP_NOMOVE | SWP_NOACTIVATE);
-
-	  EndDeferWindowPos (handle);
+	  handle = DeferWindowPos (handle,
+				   FRAME_W32_WINDOW (f),
+				   HWND_TOP,
+				   0, 0, 0, 0,
+				   SWP_NOSIZE | SWP_NOMOVE | SWP_NOACTIVATE);
+	  if (handle)
+	    {
+	      handle = DeferWindowPos (handle,
+				       GetForegroundWindow (),
+				       FRAME_W32_WINDOW (f),
+				       0, 0, 0, 0,
+				       SWP_NOSIZE | SWP_NOMOVE |
+				       SWP_NOACTIVATE);
+	      if (handle)
+		EndDeferWindowPos (handle);
+	    }
 	}
     }
   else
     {
-      my_set_foreground_window (FRAME_W32_WINDOW (f));
+      my_bring_window_to_top (FRAME_W32_WINDOW (f));
     }
 
   UNBLOCK_INPUT;

=== modified file 'src/w32term.h'
--- src/w32term.h	2012-01-19 07:21:25 +0000
+++ src/w32term.h	2012-05-28 17:22:40 +0000
@@ -576,7 +576,8 @@ do { \
 #define WM_EMACS_HIDE_CARET            (WM_EMACS_START + 18)
 #define WM_EMACS_SETCURSOR             (WM_EMACS_START + 19)
 #define WM_EMACS_PAINT                 (WM_EMACS_START + 20)
-#define WM_EMACS_END                   (WM_EMACS_START + 21)
+#define WM_EMACS_BRINGTOTOP            (WM_EMACS_START + 21)
+#define WM_EMACS_END                   (WM_EMACS_START + 22)
 
 #define WND_FONTWIDTH_INDEX    (0)
 #define WND_LINEHEIGHT_INDEX   (4)